The present invention pertains generally to electronic circuits and is more particularly directed toward novel electronic circuits that may be used in a wide range of applications with improved performance as compared to the performance achieved by conventional circuits.
Electronic circuits are used in a wide range of applications including amplification, signal generation, power regulation, digital memory, filtering, signal detection, and phase splitting. Although each application has unique needs, there is an interest common to many of such applications to improve circuit performance by reducing power requirements and reducing circuit complexity. Other areas of wide interest in applications such as amplification and signal generation include a desire to increase bandwidth, reduce noise, increase operational stability, improve input and output impedances, reduce stray inductive and capacitance, and reduce the so called Miller capacitance effect.
An object of the present invention is to provide a circuit that can be used in a wide range of applications to provide improvements like those mentioned above. In many cases, this object is achieved by reducing the complexity of circuits. Reduced complexity is often desirable because it generally offers advantages like reduced power losses, reduced space required to implement the circuit, and reduced stray inductance and capacitance. In other cases, this object is achieved by using circuit components in ways that allow advantageous characteristics of the circuit components to be exploited while avoiding their disadvantageous characteristics.
According to one aspect of the present invention, a differential amplifier circuit includes a first device of a first conductivity type comprising a first terminal coupled to an inverting input, a second terminal coupled to an output and coupled to a first potential, and a third terminal, wherein the first device alters magnitude of current that flows through the third terminal in response to a signal applied to the first terminal; a second device of a second conductivity type that is complementary to the first conductivity type comprising a fourth terminal coupled to the non-inverting input, a fifth terminal, and a sixth terminal coupled to a second potential, wherein the second potential differs from the first potential and the second device alters magnitude of current that flows through the fifth terminal in response to a signal applied to the fourth terminal; and a coupling in which potentials float with respect to the first potential and the second potential and that couples the fifth terminal to the third terminal such that a current flows between the first and second potentials through the first and second devices; wherein the differential amplifier provides an output signal at the output having a third potential that differs from the second potential, wherein the difference between the third potential and the second potential varies inversely with the signal applied to the inverting input and varies directly with the signal applied to the non-inverting input.
According to another aspect of the present invention, a phase-splitting circuit includes a first device of a first conductivity type comprising a first terminal coupled to a first input, a second terminal coupled to a first output and coupled to a first potential, and a third terminal, wherein the first device alters magnitude of current that flows through the third terminal in response to a signal applied to the first terminal; a second device of a second conductivity type that is complementary to the first conductivity type comprising a fourth terminal, a fifth terminal, and a sixth terminal coupled to a second output and coupled to a second potential, wherein the second potential differs from the first potential and the second device alters magnitude of current that flows through the fifth terminal in response to a signal applied to the fourth terminal; and a coupling in which potentials float with respect to the first potential and the second potential and that couples the fifth terminal to the third terminal such that a current flows between the first and second potentials through the first and second devices; wherein the phase-splitting circuit provides an output signal at the first output having a third potential that differs from the second potential, wherein the difference between the third potential and the second potential varies inversely with the signal applied to the first input, and wherein the phase-splitting circuit provides an output signal at the second output having a fourth potential that differs from the second potential, wherein the difference between the fourth potential and the second potential varies directly with the signal applied to the first input.
Another aspect of the present invention pertains to a method of operating a first device and a second device in a differential amplifier. The first device is of a first conductivity type, has a first terminal coupled to an inverting input, has a second terminal coupled to an output and coupled to a first potential, and has a third terminal; the second device is of a second conductivity type that is complementary to the first conductivity type, has a fourth terminal coupled to a non-inverting input, has a fifth terminal coupled to the third terminal by a coupling, and has a sixth terminal coupled to a second potential that differs from the first potential; and a current flows between the first and second potentials through the first and second devices. The method includes receiving a first input signal at the inverting input, wherein the first device alters magnitude of the current passing through the first device in response to the first input signal; passing the current through the coupling such that potentials within the coupling float with respect to the first potential and the second potential; receiving a second input signal at the non-inverting input, wherein the second device alters magnitude of the current passing through the second device in response to the second input signal; and providing an output signal at the output having a third potential that differs from the second potential, wherein the difference between the third potential and the second potential varies inversely with the first signal and varies directly with the second signal.
A further aspect of the present invention pertains to a method of operating a first device and a second device in a phase-splitter circuit. The first device is of a first conductivity type, has a first terminal coupled to an input, has a second terminal coupled to a first output and coupled to a first potential, and has a third terminal; the second device is of a second conductivity type that is complementary to the first conductivity type, has a fourth terminal, has a fifth terminal coupled to the third terminal by a coupling, and has a sixth terminal coupled to a second output and coupled to a second potential that differs from the first potential; and a current flows between the first and second potentials through the first and second devices. The method includes receiving an input signal at the input, wherein the first device alters magnitude of the current passing through the first device in response to the first input signal; passing the current through the coupling such that potentials within the coupling float with respect to the first potential and the second potential; providing a first output signal at the first output having a third potential that differs from the second potential, wherein the difference between the third potential and the second potential varies inversely with the input signal; and providing a second output signal at the second output having a fourth potential that differs from the second potential, wherein the difference between the fourth potential and the second potential varies directly with the input signal.
The various features of the present invention and its preferred embodiments may be better understood by referring to the following discussion and the accompanying drawings in which like reference numerals refer to like elements in the several figures. The contents of the following discussion and the drawings are set forth as examples only and should not be understood to represent limitations upon the scope of the present invention.